What are the causes of engine oil deterioration?

[SanStella]

Engine oil deterioration can be caused by filter failure or engine water ingress, as detailed below: Filter Failure: During use, the air filter may wear out or become damaged, allowing external dust to easily enter the crankcase through the cylinder. This increases the viscosity of the engine oil, reducing its lubricating properties. In some cases, it may clog the oil filter, causing the engine to malfunction, leading to damage and shortening its service life. Engine Water Ingress: The most common cause of engine oil deterioration is water contamination, which can turn the oil into an emulsion and disrupt the oil film. When the water content exceeds 0.1%, the antioxidants and detergent dispersants added to the oil become ineffective. If the water content reaches 1% or more, the lubricating properties of the oil deteriorate, and its viscosity decreases. In severe cases, this can lead to mechanical failures such as engine seizure or bearing damage.